a. Field of the Invention
The present disclosure relates generally to image generation in medical device mapping systems. More particularly, the present disclosure relates to generation of two-dimensional images from three-dimensional models.
b. Background Art
Current intracardiac navigational and mapping systems use a three-dimensional (3D) data representation in which a 3D geometric model of the endocardium is drawn on a computer display. Typical systems involve the use of one or more catheters to simultaneously map the heart while measuring voltages therein. The 3D geometric model is generated using data obtained by one or more electrodes on the catheters. While 3D geometric models allow viewing cardiac surfaces and various diagnostic maps at any angle by rotating them on a computer screen, the user does not see the whole cardiac surface at any time. In addition, in some situations the user cannot see the full picture of the catheter with respect to the cardiac surface geometry because there are background elements of the cardiac surface geometry that are obstructed by graphical elements of the cardiac surface geometry in the foreground.
In displaying 3D geometric models, such as 3D cardiac models of the heart, on a two-dimensional (2D) display, it is often difficult to see the entire diagnostic map (e.g. voltage map) at the same time. Thus, the 3D geometric model must be rotated in order to see different areas of the model. Furthermore, if the diagnostic map has animated graphics, the user may not be able to see the entirety of the graphics simultaneously because the animation will be running on the whole model (background and foreground) when the model is rotated. As the result, certain diagnostic map features and patterns might be difficult to identify using only a 3D geometric model of the heart.
Recent advancements in mapping technology have involved unfolding of 3D images into two-dimensional maps. For example, U.S. Pat. No. 7,542,595 to Moreau-Gobard describes unfolding of a 3D heart image using a ray-casting technique in order to more fully visualize coronaries and vessels on the surface of the heart. However, unfolding by such a technique produces significant distortion of the heart, rendering the resulting 2D image difficult to decipher.